To tune! or not to tune?... That is the question!.
 

On all of my other car I have used a tuning box called "Tunit" not for the extra power! But for the gain in mpg. I know a lot of boxes out there (Most cheap ones) just simply fool the engine into thinking it's cold and pump more fuel into the engine. Anyone using a box on there GV? If so... What make and any gains?:D

Steinbauer are very good make so I've heard. But cost more than the Tunit boxes of almost 500 notes new...

If your "tuning" intention is to save fuel, I might have some interesting and unexpected data for you in due course. ATM I'm still in the proving stage. It is to do with my IOD mod.

Leedsman.

Now you've got me very interested my mate:D If there is anyway of getting more mpg out of these oil burners! I would love to see resultx :)

Well, Timmy Tim, you can easily do the experiment yourself.
Tape down the bonnet/hood security switch on the RHS., then remove the IOD fuse and run it like that. You will of course lose the security and the keyfob door unlocking, and some new procedures will be noticed after switching on the ignition.

1) The "clocks" in front of you will do the sweep routine. I assume this is re-initializing the micros. It will do this every time.
2) The heater comes on set at 72*F.
3) Upon cranking after the glowplug light has extinguished, the engine starts normally when cold, i.e. accelerator left alone. But when hot, the accelerator needs a "prod" to get the engine to catch immediate. This could be a clue as to some alteration in fuel supply, as this is different from before, i.e. the engine started hot without touching the accelerator.

Initially at least, there seems to be a noticeable improvement in fuel consumption, using both the car's computed readout figure and the brim-brim manual calculation, but as I say, it's not yet proven. It seems essential NOT to go back to normal, fuse-in-place running.

If this DOES become proven, I'm at a loss as to why this effect is present. Doesn't make sense to me -- but then, that's microprocessors for you!

Note that if I didn't keep a strict eye on fuel consumption, I would never have known about this.

Leedsman.